Posted
by
timothyon Tuesday March 17, 2009 @12:33PM
from the logically-if-she's-made-of-wood dept.

Brietech writes "This is a homebrew laptop project based on a Picaxe microcontroller. It has 16kb of RAM, 256kb of storage, sound and a self-hosted development environment! It has a simple CLI, file-system, 'EMAXE' text editor and a programming language called 'Chris#.' Oh, and yes, it runs Linaxe."

Actually, it probably isn't. It's probably not even close. The site is slashdotted badly, but I'm guessing this is an 8-bit CPU. Most microcontrollers of this sort take several clocks per instruction. And the instruction set is probably more limited in capability than x86.

Also, I have to wonder why use an obscure part rather than the Atmel chips that are wildly popular with open source enthusiasts, or even the Microchip PICs (not quite as popular as the Atmels, but still has a strong hobbyist following). Having a development community and existing software base is useful.

If you check out the Coral Cached version of the site [nyud.net], you can see that the guy is not after something with an existing development community or software base. He's written his own everything, and seems to have a sense of humor about it. He even implemented Pong, and says that he someday hopes to achieve parity with an early 80s computer:)

Well, after a far-too-long hiatus, I'm back with a new Picaxe-based laptop! This project was born of a desire to see how far I can push the lowly Picaxe microcontroller. A friend of mine likened it to "spending over a year to reinvent the square wheel."

He's doing it as a hobby, and he's not pretending that it is useful. He compares it to a "square wheel"!

OK. So you're criticizing someone for not being as lazy as you? Way to go. This is a new level to revelling in laziness.

I remember fondly one of my udergrad design classes in which we built an 8088 system from scratch by wire-wrapping the crystal, interrupt controller, memory controller, etc. and then programmed it to make some kind of control system. I made an infusion pump controller.

Actually, it probably isn't. It's probably not even close. The site is slashdotted badly, but I'm guessing this is an 8-bit CPU. Most microcontrollers of this sort take several clocks per instruction. And the instruction set is probably more limited in capability than x86.

Well, the site is woefully uninformative, and this "manufacturer" looks just as a repackager who has burnt a specific microcode on a PIC microcontroller.... OR an Atmel AVR. Now, what you said above is true for PIC microcontrollers, as well as the older Intel 8051 and Motorola 68HC11. But it's not true for Atmel's AVR, which are 8 bit, but with a RISC core, so each instruction is executed in one cpu clock. And AVRs are indeed pretty fast beasts. The PICs are more popular among some hobbists, but not in the industry.

Except for the built in BASIC on the Picaxe the AVRs have a lot going for em. I have also pondered the idea of building a low tech computer just to see how much could be done on something that would bring the term 'low power' back down to Model 100 levels and perhaps even finally surpass 1980's tech.

You can get MRAM in the same package as the old school SRAM and some of the AVRs have an external memory interface that appears compatible. So that would allow some really deep sleeping, just push everything o

I have also pondered the idea of building a low tech computer just to see how much could be done on something that would bring the term 'low power' back down to Model 100 levels and perhaps even finally surpass 1980's tech.

Check out TI's MSP430 series... About a quarter milliamp per MIP... the fastest one they sell should then draw about 6 mA, probably less than the power indicator will draw.

I use PICs rather than AVRs myself, so I can only speak to the PICs. Many of the PICs have a deep sleep mode that keeps the RTCC running. The main clock can use one high speed crystal and the RTCC a secondary 32.768kHz crystal. In this mode it draws about 1uA. I assume there are Atmel parts available with a similar feature. A dedicated chip will be noticeably lower power -- about 250nA -- but that adds an extra part. 1 uA is a low enough draw that a CR2032 won't run down before its shelf life expires.

Atmel is SO much better than any PIC. Atmel AVR microcontrollers are individually cheaper. They run at least four times faster for the same clock speed (one instruction per clock cycle instead of one instruction per four clocks for the PIC). They have a vastly more versatile and flexible instruction set. The AVRs are designed to be used with high level languages like Open Source GCC, not kluged BASIC for high school kids that the PICs use in their absurdly overpriced 'training' packages. Most AVRs now

"Most microcontrollers of this sort take several clocks per instruction."

Isn't that the most common scenario on modern processors as well? The difference is that with an 8 bit microcontroller you can easily determine the number of clock cycles per instruction, on most of today's microprocessors you usually can't.

Most modern CPUs have a lot of instructions in flight, though; the result is an average of more than one instruction per clock (unless it's stalling badly on cache misses). The PICs, for example, execute one instruction every four clocks, with very little variation (branches and a couple other instructions take 8 clocks, but there's never any variation).

Anyway, some Wikipedia reading says I was wrong in part -- the 286 averaged about 0.21 instructions per clock. But it's still faster than a comparably clo

I got a kick out of reading his blog. Seems like a really neat project to learn how computers work at the lowest level.

I agree with you about the choice of microcontroller, though. Atmel AVRs are very popular, and are available in significantly more powerful varieties. Check out this one [atmel.com]; it has 16KiB of S-RAM on the CPU, so you can save yourself the 2x8KiB chips he used, which means reduced cost.

Another one to consider is the Parallax Propeller [parallax.com]. They aren't too popular, but have impressive capabilities, ig

The new Microchip PIC32 series has a 32-bit RISC core, single instruction per cycle at 80 Mhz and its nominally the same price as the older 8-bit micros (i.e. within a dollar or two). Moore's law applies to microprocessors, and 8-bit is on the way out.

8 bit will never be on the 'way out'. It's just too convenient for most tasks and all that happens is that the price just keeps getting pushed down. If there's spare die space due to process shrinkage (hah!) they can always cram in another timer or such to make the whole device more appealing.

I started the Vista Ultimate install on one of these in November of '08, so far the install has made it up to 6%.The biggest problem is deleting most of the so far installed files to make room for the other 94% of the remaining install; damn all of those 'out of memory' and 'out of drive space' error messages.Plus, Vista throws a major hissy fit when you do try to delete some of the install files!

if you were in the woods with nothing but a hatchet, how long before you could send an email?

Even if you knew everything - it would literally take decades to do it "right." It took the entire human race with practically unlimited resources about 132 years once we had the most basic understanding of electronics (telephone). Even knowing every concept doesn't put you ahead by much without an existing manufacturing base.

"Unfortunately, it would have only been able to send messages to Princes in Nigeria, thus not being able to render them help in getting of the island."

Give the guy a break! He was already to the point of sending to SOMEONE. In a few days he probably could've sent an email to anyone. Too bad that idiot Gilligan knocked over and broke the Professor's coconut e-mailer. Funny how the idea was workable expect for one flaw not associated with the actual plan and instead of trying again they just abandoned it

What if you are in the woods without even a hatchet? How long until you have a simple hatchet?

Probably not all that long until most people have some sort of edge to work with (find 2 stones, smash, presto!). But how long until you come up with something that is reasonably light and has a handle?

He posed the question, if you were in the woods with nothing but a hatchet, how long before you could send an email?

As long as it takes for some hiker with a smartphone to come by, plus a few minutes to clean the blood off the hatchet.

This device may not compare favorably with commercially available computing platforms, but having people in our society with curious minds and an ability to make things is invaluable.

Agreed - this is a very cool project.

I have recently been working with amateur packet radio, which is somewhere in between the linked project and modern technology. In addition to a computer you only need a radio transceiver and some simple circuitry connecting it to the audio in/out ports, and you can send email to a similarly-equipped station within the range of your radio (at speeds betw

First, you need to find some pigeons or some other suitable birds. You will also figure out how to make something resembling paper (shouldn't be too difficult with all the wood in the woods), and some means to write (something suitable should be available as well)

Once you managed to train some of them to deliver messages, you send one asking for RFC791 and RFC793, unless you're a networking expert and know them from memory. RFC 792 would be also recommended. You will also need RFC 1149, but that one is short and is best memorized before you get lost in the woods. Optionally, RFC 2549 could provide better service.

The next thing to do is to implement RFC 1149, and use that to talk to a mail server. Anybody with some mail experience should know how to use mail over a telnet session. Just make sure to memorize the IP addresses of a SMTP and a POP3 server (no problem if you run your own server and remember the address). Then just connect and send something like:

Latency could be a bit annoying with having to send all those pigeons back and forth, and a good spam filter would be needed server-side if you don't want to spend weeks getting rid of it before you get anything useful, but in a couple of weeks it could be done.

Once this is going, the next step would be starting an open source project to implement IP over smoke signals, or optical telegraph, in case something happens to the pigeons, and to reduce latency. Also implementing DNS would help with talking to the rest of the net.

Once all this is working you can start really improving your tech, by requesting pages from wikipedia on anything you don't know enough about.

Good for adults, who build it. I don't think you get the idea behind doing most projects like this. It isn't to have some amazingly practical tool or to make money but to learn, explore, and prove you can do it yourself. This is the same type of comments people posted when the article about the non-von1 was on here. Give credit to the DIYers for doing these amazing things themselves with limited budgets.

Ah, I see. I guess I'm accustomed to writing for microcontrollers, so I never saw that as a barrier. I've even done a design [spatula-city.org] with a related PIC part (PIC16 instead of PIC32), which is why I wondered about the specs on this PICaxe.

If it were me making this sort of laptop, I'd just write my "OS" in C and compile with GCC and be on my merry way.:-) I guess to get to the "self-hosting development" level, though, I'd be wise to get some sort of interpreted language on there, a'la the old BASIC computers of t

If you buy the PIC32 I mentioned, it's a powerful low-cost machine, but it's a bit like buying a crate engine, tranny and chassis to build a race car. You better be, or have access to, a competent mechanic to put it together, and you'll have your purpose-built race car.

It sounds like the PICaxe is more like buying a Camry off the lot. It's got all the accoutrements and is ready to go. Turn the key, put it in gear, and you're on the road.

Yea, I am a long time customer of MicroChip. I have had nothing but great experiences with them. And for what it's worth, you can get C, Pascal, and Basic compiler IDEs from mikroe.com optimized for all their microcontrollers.

I have one of MikroElektronika's boards. It hasn't been a perfect experience, but it got me started quickly. You can see some of my Mad Scientist stuff here [spatula-city.org]. I used the dsPIC33 to emulate video game cartridges in software.:-)

Of course you can buy a 486 [ebay.com] at comparable prices. But I don't think that was the point. He built the circuits, the laptop case, OS, interpreter and applications all from scratch. I think the point is to be a hardhack similar to ones from the Homebrew computer clubs of the past.

Well, after a far-too-long hiatus, I'm back with a new Picaxe-based laptop! This project was born of a desire to see how far I can push the lowly Picaxe microcontroller. A friend of mine likened it to "spending over a year to reinvent the square wheel." The specs, you ask? This bad boy is decked out to the max:

A PICAXE microcontroller is a Microchip PIC microcontroller that has been pre-programmed with the PICAXE bootstrap code. The bootstrap code enables themicrocontroller to be reprogrammed without the need for an (expensive)conventional programmer, making the whole download system a very low-costsimple serial cable!The bootstrap code also contains common routines (such as how to generate apause delay or a sound output), so that each download does not have to waste timedownloading this commonly required data. This makes the download time muchquicker.

I'm sure this "laptop" would have been much faster if based around an AVR. But that would have required more work.

yes, building a board to program a picaxe chip requires little more than a 7805 and a single 2.2K resistor.

it runs a lot slower than a conventional pic chip, (but how often do you really need full speed for a microcontroller?)Best of all, you can write your code entirely in BASIC, no need for messy assembly. (my sig should make it clear why this is a plus for me)

and, if you do need the extra speed, and you are all out of pic chips, you can put a picaxe chip in a standard pic programmer, and it will over-wr

it runs a lot slower than a conventional pic chip, (but how often do you really need full speed for a microcontroller?)Best of all, you can write your code entirely in BASIC, no need for messy assembly. (my sig should make it clear why this is a plus for me)

Since you don't even have a.sig, I am confused whether you're trying to be hilarious or are actually even more forgetful than I am - which is not good.

The idea of running Linux on a PicAxe microcontroller must excite a lot of people... Every link to a project or explanation of "linaxe" results in 404 errors [chrisfenton.com] and more 404 errors [sourceforge.net].

My Sharp PC 1403H [thimet.de] has 200+ hrs uptime on two buttoncells under full load. It's predecessor (my very first computer, bought back in 1986) has the same specs but only 4KB RAM instead of 32. I have yet to find a portable computer that can beat it's uptime off the grid. The Palm m105 with folding keyboard came the closest, but still was 160+ hrs short with it's mere 40 hrs battery time under load.

Does this baby have that potential? That would actually make it interesting, even today.

It is still better than bluehost. At least dreamhost is more upfront about what you can and cannot do and they specifically say that your if your website is just a normal website such as a blog that it will not be taken down due to being slashdotted, dugg, etc.

But on another note....I want that laptop. Its so awesome. That one of those things that you do just to say you did it and to show off your 1337ness.

Christ I must say..you have done quite a good job proving your 1337ness and I commend you ^_^

...a cigar humidor, except for the cheesy brass bits on the corners. In fact, if it ever goes balls up, rip out the guts and give it to me. I've got a handful of La Gloria Cubanas and a few Camacho El-Legendarios that would fit in there very nicely.